The present invention relates to an automatic exposure control apparatus for television cameras for automatically setting the exposure to light incident on the target of the television camera tube in response to a feedback control signal derived from a video signal, wherein the video signal is modulated in amplitude with a predetermined waveform generated in response to a synchronization pulse.
In the known television camera, the video signal is utilized for purposes of controlling the amount of light incident on the target surface. It is sometimes the case however when an extremely bright scene suddenly comes into view during a camera movement, the amount of incident light is reduced according to the maximum peak value of the video signal so that the intensity of the light incident on the relatively dark area of the televised view is excessively reduced.
A prior art approach to this problem involves detecting a video signal derived from a center area of the target surface and adjusting the exposure setting in response thereto. This prior art approach is also unsatisfactory since it results in a peripheral area of the target being over-exposed if that area has an extremely high brightness compared with the center area, which often occurs when the upper area of the scene is occupied with a clear sky view while the other part of the scene has a low brightness level.